Considerations Before Labeling All Samples Under the E-Z21175 Branch as Oromo
YFull uses an average mutation rate of 144.41 years, focusing only on SNPs from the combBED region for TMRCA estimation, with adjustments for each sample’s length coverage for age.
YFull age estimation methodology
The average mutation rate for Y chromosome SNPs used by FTDNA is between 80 and 144 years. This rate is highlighted in a video at
Family Tree DNA's Big Y Block Tree starting at the 6:30 mark. Using FTDNA's mutation rate range (80 to 144 years), we can approximate the average mutation rate for Y chromosome SNPs in genealogical studies to be around 112 years (80+144)/2. However, it's important to note that the mutation rate can vary between different haplogroups and even between related branches.
Imagine a scenario 4,000 to 5,000 years before present (YBP) involving a man carrying the Z813 mutation. If this man had multiple sons, it’s possible that none or just one of his sons would develop a new mutation. The average mutation rate of 121 years suggests that it might take many years after the initial ancestor’s passing for new mutations to appear. It’s unlikely for each son to have a unique mutation used in genealogical studies.
Historically, groups of people did not subdivide based on their genetic mutations, as these changes are not visibly apparent. They likely remained as one community. Over time, some men within these groups would have sons with new mutations, while their brothers’ sons might not, although their grandkids or great-grandkids could have new and different mutations. As these groups spread and split, they did not segregate based on genetic mutations. Consequently, individuals with different mutations often remained in the same group, maintaining familial ties. This means that men with the Z21175 mutation could have stayed with their family members who did not have this specific mutation. Meanwhile, others with and without the mutation might have separated and moved to different geographical locations. This explains why we are likely to see more Oromo samples under
E-Y17859 and more Somali samples under
E-Z21175. I am only focusing on the Somali and Oromo samples, but I am not suggesting all the samples under Z813 are either Somali or Oromo.
If someone suggests that people who have been part of their Somali family for over a thousand years are not Somali, ask them to provide evidence to support their arguments. When their arguments are based on YFull and FTDNA branches, inquire if they understand the mutation rate for those SNPs and whether it could cause related people who stayed together for centuries to accumulate different mutations.
We know from
@BluSkee and YFull profiles that two of the SDPP samples are
YF095342 Howrarsame from Gedo region and
YF081756 Dhulbahante from Sool region, and sample ID
YF102772 belongs to Ajuuraan > Gareen > Walmuge from Baardheere Gedo. New Somali samples are also expected to join this branch.
There is no scientific evidence supporting the labeling of E-Z21175 as Oromo. Referring to individuals outside of their identified lineage is disrespectful. Therefore, I urge everyone to not alienate the Somalis under E-Z21175.
Useful information for understanding the mutation rate:
(PDF) Defining a New Rate Constant for Y-Chromosome SNPs based on Full Sequencing Data (researchgate.net)
Mutation Rate Variability across Human Y-Chromosome Haplogroups | Molecular Biology and Evolution | Oxford Academic
